- [Voiceover] Traveler's
diarrhea is caused by a bacteria known as enterotoxigenic E. coli. It's often referred to
as Montezuma's Revenge if contracted in Mexico and as Delhi Belly if contracted in India. The bacteria itself is
usually transmitted via the fecal to oral route. That is, you may eat some kind
of food or drink some water that's been contaminated with feces and that feces was
contaminated with the pathogen. Once you ingest this pathogen,
it'll make its way past the stomach and into the small intestine. So like always, we're gonna
focus on this green layer over here, known as the epithelium. We'll focus in on one of
those epithelial cells. The bacteria will look something like this and it'll actually try to
physically associate with the epithelial cell using
the structures known as pili, which is just plural for pilus. Once it's associated
with the epithelial cell, it'll release two
different types of toxins to help it enter that cell. The first is known as
heat-labile enterotoxin and the second is known as
heat-stable enterotoxin. Heat-labile just basically
means that this enterotoxin is going to be inactivated
at high temperatures. Heat-stable means that this
enterotoxin will be stable at high temperatures. So eventually these enterotoxins
will help the bacteria enter the epithelial cell. Once the bacteria is in the
epithelial cell however, it'll continue to release
those enterotoxins. These enterotoxins will
then act on different enzymatic pathways and
biochemical signaling pathways. But they'll have the same end result. They'll cause the secretion
of water and chloride, and in addition, they'll prevent
the reabsorption of sodium. So what you're doing is
you're actually squeezing the contents of the epithelial cell out into the lumen of the small intestine. Notice this is actually a
pretty similar mechanism to the way that the cholera toxin works. In fact the heat-labile
enterotoxin acts on the same enzymatic pathway that
the cholera toxin does. When this bacteria enters your system, it'll cause all sorts
of different symptoms, much like the other
forms of gastroenteritis. Usually the symptoms start
within hours after exposure and it lasts for about a few days. Given that the bacteria
operates similarly to cholera, a lot of the symptoms will be similar. This includes profuse watery
diarrhea, dehydration, and like all other
forms of gastroenteritis you may experience some
nausea and vomiting. You may also experience
some cramps in your abdomen. If you go to the doctor, like
always, they're going to order a stool sample. That stool sample will be
evaluated for its contents and if they see that you have
the enterotoxigenic E. coli, then there's a good chance that you have traveler's diarrhea. There aren't really that many
treatments explicitly for traveler's diarrhea, except
to drink a lot of water. Remember that your small
intestine is actually expelling the water from its own system, so you're going to be
experiencing a lot of dehydration. If you want to prevent
getting traveler's diarrhea while you're traveling, the
best thing to do is to drink bottled water or really
just any water that you know for sure is clean because
in doing so you could avoid the risk of drinking some
water that's been contaminated with the pathogen.